welcome to helath care magic forum ,
in your case diagnosis is required but more then dignosis treatment is required as you have been suffering from more than 4 yrs and still not better ,
might be the cause for your hairloss as well
for dandruff and hairfall homoeopathic medicnes are best , consult a homoeopath
thse medices are vey safe , natural , effective and without any side effects
if its an dandruff , which is an infection and need to be treated internally then externally, but dont worry these medicnes will surely help u out.